JP6965935B2 - Cross-flow filtration device, cross-flow filtration method - Google Patents

Description

The present invention relates to a cross-flow filtration device and a cross-flow filtration method.

In recent years, carbon materials having a size in the nanometer range (hereinafter referred to as "nanocarbon") are expected to be applied to various fields due to their mechanical properties, electrical properties, chemical properties and the like.
When nanocarbon is used as an electronic material, for example, it is used in the form of a nanocarbon dispersion liquid in which nanocarbon and a surfactant are dispersed in a solvent.

The dispersion liquid containing the surfactant needs to remove the excess surfactant depending on the subsequent usage method. Conventionally, as a method for removing a surfactant, for example, a static dialysis method (filtration method) has been used. Examples of the method for producing the nanocarbon dispersion liquid using the filtration method include a step of wetting the crude carbon nanotubes with a solvent containing water, and a step of acid-treating the crude carbon nanotubes with an aqueous solution containing nitric acid. A method having a step of filtering the reaction solution obtained in the previous step and a step of filtering the reaction solution is known (see, for example, Patent Document 1). Further, there is known a method of purifying a dispersion liquid by cross-flow filtering a crude dispersion liquid obtained by mixing a fibrous carbon nanostructure with nitric acid and pure water using a ceramic membrane (see, for example, Patent Document 2). ..

Japanese Unexamined Patent Publication No. 2008-133178 JP-A-2017-119586

However, the methods described in Patent Document 1 and Patent Document 2 are low in efficiency because the processing time is long. Further, it is difficult to determine the end of the surfactant removal treatment by the methods described in Patent Document 1 and Patent Document 2. Therefore, in the methods described in Patent Document 1 and Patent Document 2, the removal treatment of the surfactant becomes excessive, the content of the surfactant in the dispersion liquid after the treatment becomes too small, and the nanocarbon aggregates. There was something.

An object of the present invention is to provide a cross-flow filtration device and a cross-flow filtration method capable of efficiently determining the end of the removal treatment in the removal treatment of excess components contained in a solution such as a dispersion liquid. do.

The cross-flow filtration device of the present invention comprises a filter module having an inner tank and an outer tank separated by a semi-transparent film, a treatment liquid tank for accommodating a treatment liquid, and the inner tank and the treatment liquid tank of the filter module. From the pump for circulating the treatment liquid, the replenishment liquid tank for accommodating the replenishment liquid to be replenished in the treatment liquid tank, at least one or more sensors for measuring the pressure of the circulating treatment liquid, and the replenishment liquid tank. A replenisher liquid measuring unit for measuring the amount of the replenisher liquid supplied to the treatment liquid tank is provided, and the replenisher liquid is continuously replenished to the treatment liquid tank.

The cross-flow filtration method of the present invention is a cross-flow filtration method using the cross-flow filtration device of the present invention, in which the treatment liquid is circulated to the inner tank and the treatment liquid tank, and the replenishment liquid tank. It is characterized by having a step of determining the end of circulation of the processing liquid according to the amount of the replenishing liquid.

According to the present invention, in the removal treatment of excess components contained in the treatment liquid, the end of the removal treatment can be efficiently determined.

It is a schematic diagram which shows the cross flow filtration apparatus of 1st Embodiment. It is a block diagram which shows the schematic structure of the control part of the cross-flow filtration apparatus of 1st Embodiment. It is a schematic diagram which shows the minimum structure of the cross-flow filtration apparatus of this invention. It is a schematic diagram which shows the cross flow filtration apparatus of 2nd Embodiment. It is a flowchart which shows the cross-flow filtration method of this invention. It is a figure which shows the relationship between the processing time and the consumption amount of the replenishing liquid in the cross-flow filtration treatment in Experimental Example 1. It is a figure which shows the relationship between the processing time and the replenishing liquid flow rate in the cross-flow filtration treatment in Experimental Example 1. It is a figure which shows the relationship between the processing time and the replenishing liquid flow rate in the cross-flow filtration treatment in Experimental Example 1. It is a schematic diagram which shows the state of the nonionic surfactant which permeates through the semipermeable membrane of a filter module. It is a figure which shows the relationship between the processing time and the replenishing liquid flow rate in the cross-flow filtration treatment in Experimental Example 2. In Experimental Example 2, it is a figure which shows the relationship between the processing time and the normalized replenishing liquid flow rate in a cross-flow filtration process. It is a figure which shows the relationship between the processing time and the replenishing liquid flow rate in the cross-flow filtration treatment in Experimental Example 3. In Experimental Example 3, it is a figure which shows the relationship between the processing time and the standardized replenishing liquid flow rate in a cross-flow filtration process. In Experimental Example 4, it is a figure which shows the relationship between the processing time and the standardized replenishing liquid flow rate in a cross-flow filtration process. In Experimental Example 4, it is a figure which shows the absorption spectrum of the single-walled carbon nanotube dispersion liquid before and after the cross-flow filtration treatment. It is a figure which shows the transmission property of the thin film transistor produced in Experimental Example 4.

Embodiments of the cross-flow filtration apparatus and the cross-flow filtration method of the present invention will be described.
It should be noted that the present embodiment is specifically described in order to better understand the gist of the invention, and is not limited to the present invention unless otherwise specified.

[First Embodiment]
(Cross flow filtration device)
FIG. 1 is a schematic view showing a cross-flow filtration device of the present embodiment.
The cross-flow filtration device 10 of the present embodiment includes a filter module 20, a treatment liquid tank 30, a pump 40, a pressure regulator 50, a replenishment liquid tank 60, a control unit 70, a replenishment liquid measurement unit 80, and the like. A first pressure sensor 90 (P _f ), a second pressure sensor 100 (P _r ), and a third pressure sensor 110 (P _p ) are provided. Further, the cross-flow filtration device 10 of the present embodiment may include a permeation liquid tank 120 and a permeation liquid measurement unit 130.

The filter module 20 has an inner tank 21 and an outer tank 22 arranged in contact with the outer periphery of the inner tank 21.
A semipermeable membrane 23 is provided between the inner tank 21 and the outer tank 22.

The treatment liquid tank 30 is for accommodating the treatment liquid 200 containing a dispersant, a dispersant and a dispersion medium.
The treatment liquid tank 30 has a suction pipe 31 for sucking the treatment liquid 200 contained therein and supplying it to the filter module 20. The tip of the suction pipe 31 is immersed in the treatment liquid 200 in the treatment liquid tank 30.
Further, the treatment liquid tank 30 has a recovery pipe 32 for recovering the treatment liquid 200 that has circulated through the filter module 20.
Further, the treatment liquid tank 30 has an injection pipe 33 for injecting the replenishment liquid 210 to be replenished from the replenishment liquid tank 60.
The treatment liquid tank 30 is airtight with a suction pipe 31, a recovery pipe 32, and an injection pipe 33.

As the permeated liquid 220 is discharged from the filter module 20, the amount of the treatment liquid 200 in the treatment liquid tank 30 decreases. Since the treatment liquid tank 30 is airtight, the inside of the treatment liquid tank 30 becomes negative pressure due to the decrease in the treatment liquid 200. Then, the pressure difference between the atmospheric pressure and the inside of the treatment liquid tank 30 becomes an attractive force, and the replenishment liquid 210 is automatically supplied from the replenishment liquid tank 60 to the treatment liquid tank 30. When the inside of the processing liquid tank 30 and the atmospheric pressure are balanced, the supply of the replenishing liquid 210 is stopped. As described above, in the cross-flow filtration device 10 of the present embodiment, the replenisher liquid 210 is continuously replenished to the treatment liquid tank 30. As a result, the amount of the treatment liquid 200 in the treatment liquid tank 30 is automatically maintained.
Therefore, in the cross-flow filtration device 10 of the present embodiment, the amount of the permeate liquid 220 discharged from the filter module 20 and the amount of the replenisher liquid 210 replenished from the replenisher liquid tank 60 to the treatment liquid tank 30 are equal. Further, the amount of the permeate 220 per unit time (flow rate of the permeate 220) and the amount of the replenisher 210 per unit time (flow rate of the replenisher 210) are slightly different due to the influence of the pulsation of the pump 40 and the like. Equal to what causes fluctuations.

The suction pipe 31 is connected to the inlet side of the inner tank 21 of the filter module 20 via the first pipe 141.
The recovery pipe 32 is connected to the outlet side of the inner tank 21 of the filter module 20 via the second pipe 142.
The injection pipe 33 is connected to the suction pipe 61 of the replenishment liquid tank 60 via the third pipe 143.

The pump 40 is for circulating the treatment liquid 200 to the inner tank 21 and the treatment liquid tank 30 of the filter module 20.
The pump 40 is provided in the middle of the first pipe 141.

The pressure regulator 50 is for adjusting the pressure in the inner tank 21 of the filter module 20. By operating the pressure regulator 50, the pressure on the semipermeable membrane 23 by the treatment liquid 200 circulating in the inner tank 21 of the filter module 20 can be adjusted.
The pressure regulator 50 is provided in the middle of the second pipe 142.
Further, instead of providing the pressure regulator 50, it is possible to adjust the pressure of the inner tank 21 of the filter module 20 by the inner diameter of the second pipe 142 and the flow velocity of circulation in the pump 40.

The replenishment liquid tank 60 is for accommodating the replenishment liquid 210 to be replenished in the treatment liquid tank 30.
The replenishment liquid tank 60 has a suction pipe 61 for sucking the replenishment liquid 210 contained therein and supplying it to the treatment liquid tank 30. The tip of the suction pipe 61 is immersed in the replenisher liquid 210 in the replenisher liquid tank 60.
Further, the replenishment liquid tank 60 has a ventilation pipe 62 for keeping the internal pressure equal to the atmospheric pressure.

The control unit 70 is electrically connected to the pump 40 via a cable 151.
Further, the control unit 70 is electrically connected to the pressure regulator 50 via the cable 152.
Further, the control unit 70 is electrically connected to the replenisher liquid measuring unit 80 via the cable 153.
Further, the control unit 70 is electrically connected to _{the first pressure sensor 90 (P f) via the cable 154.}
Further, the control unit 70 is electrically connected to _{the second pressure sensor 100 (Pr) via the cable 155.}
Further, the control unit 70 is electrically connected to _{the third pressure sensor 110 (Pp) via the cable 156.}
The control unit 70 controls the operation of the pump 40 based on the amount of the replenisher liquid 210. Further, the control unit 70 can also control the operation of the pump 40 based on the signals from the first pressure sensor 90, the second pressure sensor 100, and the third pressure sensor 110.

As shown in FIG. 2, the control unit 70 has an acquisition unit 70a for acquiring the amount of the replenishment liquid 210 supplied from the replenishment liquid tank 60 to the treatment liquid tank 30 measured by the replenishment liquid measurement unit 80, and an acquisition unit 70a. Based on the amount of the replenisher liquid 210 acquired in 70a, the determination unit 70b that determines the end of the circulation of the treatment liquid 200 and the pump 40 when the determination unit 70b determines the end of the circulation of the treatment liquid 200 are over. It is functionally provided with a stop unit 70c that sends a stop command after the processing time has elapsed.
In the present embodiment, the determination unit 70b determines the end by determining that the amount of the replenisher 210 acquired by the acquisition unit 70a has reached a predetermined value.

The replenishment liquid measuring unit 80 is for measuring the amount of the replenishing liquid 210 supplied from the replenishing liquid tank 60 to the treatment liquid tank 30. The replenishment liquid measuring unit 80 measures the liquid amount of the replenishing liquid 210 in the replenishing liquid tank 60 and the change (flow velocity) of the liquid amount of the replenishing liquid tank 60 per unit time.

The first pressure sensor 90 (P _f ) is for measuring the pressure of the processing liquid 200 on the inlet side of the inner tank 21 of the filter module 20.
The first pressure sensor 90 (P _f ) is provided near the inlet of the inner tank 21 of the filter module 20 in the first pipe 141.

The second pressure sensor 100 ( _Pr ) is for measuring the pressure of the processing liquid 200 at the outlet side of the inner tank 21 of the filter module 20.
The second pressure sensor 100 ( _Pr ) is provided near the outlet of the inner tank 21 of the filter module 20 in the second pipe 142.

The third pressure sensor 110 (P _p ) is for measuring the pressure of the permeation liquid 220 that has passed through the semipermeable membrane 23 on the discharge port 24 side of the outer tank 22 of the filter module 20.
The third pressure sensor 110 (P _p ) is provided in the vicinity of the discharge port 24 of the outer tank 22 of the filter module 20 in the fourth pipe 144.

The permeation liquid tank 120 is for collecting the permeation liquid 220 discharged from the discharge port 24.
The permeation liquid tank 120 has a recovery pipe 121 for collecting the permeation liquid 220 discharged from the discharge port 24. The tip of the recovery pipe 121 is immersed in the permeate 220 in the permeate tank 120.
The recovery pipe 121 is connected to the discharge port 24 of the outer tank 22 of the filter module 20 via the fourth pipe 144.
Further, the permeation tank 120 has a ventilation pipe 122 for keeping the internal pressure equal to the atmospheric pressure.

The permeation liquid measuring unit 130 is for measuring the amount of the permeation liquid 220 discharged from the discharge port 24. The permeation liquid measuring unit 130 measures the liquid amount of the permeation liquid 220 in the permeation liquid tank 120 and the change (flow velocity) of the liquid amount of the permeation liquid tank 120 per unit time.

The inner tank 21 of the filter module 20 has a space (flow path) through which the treatment liquid 200 can pass. The shape and size of the inner tank 21 of the filter module 20 are not particularly limited as long as the treatment liquid 200 can pass therethrough.

The material of the inner tank 21 is not particularly limited as long as it is stable with respect to the treatment liquid 200 and the replenisher liquid 210. Examples of the material of the inner tank 21 include glass, polycarbonate, polypropylene and the like.

The outer tank 22 of the filter module 20 has a space (flow path) through which the permeated liquid 220 that has passed through the semipermeable membrane 23 can pass. The shape and size of the outer tank 22 of the filter module 20 are not particularly limited as long as the permeated liquid 220 can pass therethrough.

The material of the outer tank 22 is not particularly limited as long as it is stable with respect to the permeate 220. Examples of the material of the outer tank 22 include glass, polycarbonate, polypropylene and the like.

The pore size of the semipermeable membrane 23 is not particularly limited as long as it is smaller than the dispersoid such as nanocarbon contained in the treatment liquid 200 and larger than the surfactant molecule. As the semipermeable membrane 23, for example, one having a pore diameter of 30 kDa to 750 kDa is preferably used.
The material of the semipermeable membrane 23 is not particularly limited as long as it is stable with respect to the treatment liquid 200 and a desired pore diameter can be obtained. Examples of the material of the semipermeable membrane 23 include polyethersulfone, polysulfone, cellulose ester, and those materials subjected to surface treatment.

The treatment liquid tank 30 has a space capable of accommodating the treatment liquid 200 and the replenisher liquid 210. The shape and size of the treatment liquid tank 30 are not particularly limited as long as they can accommodate the treatment liquid 200 and the replenisher liquid 210.

The material of the treatment liquid tank 30 is not particularly limited as long as it is stable with respect to the treatment liquid 200 and the replenisher liquid 210. Examples of the material of the treatment liquid tank 30 include glass, polypropylene, polyethylene, Teflon (registered trademark) resin, stainless steel and the like.

The materials of the suction pipe 31, the recovery pipe 32, and the injection pipe 33 are not particularly limited as long as they are stable with respect to the treatment liquid 200 and the replenisher liquid 210. Examples of the material of the suction pipe 31, the recovery pipe 32 and the injection pipe 33 include glass, polypropylene, polyethylene, Teflon (registered trademark) resin and the like.

The pump 40 is not particularly limited as long as it can circulate the treatment liquid 200 to the inner tank 21 and the treatment liquid tank 30 of the filter module 20. Examples of the pump 40 include a liquid feed pump.

The pressure regulator 50 is not particularly limited, and examples thereof include a pinch valve and the like.

The replenishment liquid tank 60 has a space capable of accommodating the replenishment liquid 210. The shape and size of the replenishment liquid tank 60 are not particularly limited as long as they can accommodate the replenishment liquid 210.

The material of the replenishing liquid tank 60 is not particularly limited as long as it is stable with respect to the replenishing liquid 210. Examples of the material of the replenishing liquid tank 60 include glass, polypropylene, polyethylene, Teflon (registered trademark) resin and the like.

The material of the suction pipe 61 is not particularly limited as long as it is stable with respect to the replenisher liquid 210. Examples of the material of the suction tube 61 include glass, polypropylene, polyethylene, Teflon (registered trademark) resin and the like.

Examples of the control unit 70 include a personal computer and the like.

The replenishing liquid measuring unit 80 and the permeated liquid measuring unit 130 are not particularly limited, and for example, a scale for measuring the weight of a general liquid or a liquid level gauge can be used. Further, a flow meter may be provided in the middle of the third pipe 143 and the fourth pipe 144.

The first pressure sensor 90, the second pressure sensor 100, and the third pressure sensor 110 are not particularly limited, and examples thereof include a pressure sensor that measures the pressure of a general liquid.

The permeation liquid tank 130 has a space capable of accommodating the permeation liquid 220. The shape and size of the permeation tank 130 is not particularly limited as long as it can accommodate the permeation liquid 220.

The material of the permeate tank 130 is not particularly limited as long as it is stable with respect to the permeate 220. Examples of the material of the permeation tank 130 include glass, polypropylene, polyethylene, Teflon (registered trademark) resin and the like.

The first pipe 141, the second pipe 142, the third pipe 143, and the fourth pipe 144 are not particularly limited as long as they are stable with respect to the treatment liquid 200, the replenisher liquid 210, and the permeate liquid 220. Examples of the first tube 141, the second tube 142, the third tube 143, and the fourth tube 144 include a tube made of silicon rubber, vinyl chloride, and polyolefin.

Note that FIG. 3 is a schematic view showing the minimum configuration of the cross-flow filtration device of the present invention.

According to the cross-flow filtration device 10 of the present embodiment, for example, in the removal treatment of the excess surfactant contained in the treatment liquid 200, which carries out the cross-flow filtration method described later, the removal treatment can be efficiently completed. Can be decided. Further, according to the cross-flow filtration device 10 of the present embodiment, for example, by implementing the cross-flow filtration method described later, the contents of nanocarbon and the surfactant are adjusted to the desired amounts with high accuracy. A treatment liquid is obtained.

[Cross-flow filtration method]
The cross-flow filtration method using the cross-flow filtration device 10 will be described with reference to FIG. 1, and the operation of the cross-flow filtration device 10 will be described.

The cross-flow filtration method of the present embodiment includes a step of circulating the treatment liquid 200 to the inner tank 21 and the treatment liquid tank 30 of the filter module 20 (hereinafter referred to as “step A”) and the treatment liquid from the replenishment liquid tank 60. It has a step (hereinafter, referred to as “step B”) of determining the end of circulation of the treatment liquid 200 according to the amount of the replenishing liquid supplied to the tank 30.

In the cross-flow filtration method of the present embodiment, the treatment liquid 200 preferably contains nanocarbon as a dispersant, a surfactant as a dispersant, and a dispersion medium.

In the cross-flow filtration method of the present embodiment, the nanocarbon is a carbon composed mainly of carbon such as single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, carbon nanohorns, carbon nanotwist, graphene, and fullerene. Means material. In the cross-flow filtration method of the present embodiment, a case where excess surfactant is removed from the treatment liquid 200 containing single-walled carbon nanotubes as nanocarbons will be described in detail.

It is known that single-walled carbon nanotubes are divided into two different properties, a metal type and a semiconductor type, depending on the diameter and winding method of the tube. When single-walled carbon nanotubes are synthesized using conventional manufacturing methods, the ratio of metallic single-walled carbon nanotubes with metallic properties to semiconductor-type single-walled carbon nanotubes with semiconductor-like properties is statistically 1: 2. A mixture of the contained single-walled carbon nanotubes is obtained.

The mixture of single-walled carbon nanotubes is not particularly limited as long as it contains metal-type single-walled carbon nanotubes and semiconductor-type single-walled carbon nanotubes. Further, the single-walled carbon nanotube in the present embodiment may be a single-walled carbon nanotube alone, a single-walled carbon nanotube in which a part of carbon is substituted with an arbitrary functional group, or a single-walled carbon nanotube modified with an arbitrary functional group. It may be a single-walled carbon nanotube.

The dispersion medium is not particularly limited as long as it can disperse a mixture of single-walled carbon nanotubes. Examples of the dispersion medium include water, heavy water, organic solvents, ionic liquids and the like. Among these dispersion media, water or heavy water is preferably used because the single-walled carbon nanotubes do not deteriorate.

As the surfactant, a nonionic surfactant, a cationic surfactant, an anionic surfactant and the like are used. In order to prevent ionic impurities such as sodium ions from being mixed into the single-walled carbon nanotubes, it is preferable to use a nonionic surfactant.

As the nonionic surfactant, a nonionic surfactant having a hydrophilic moiety that does not ionize and a hydrophobic moiety such as an alkyl chain is used. Examples of such a nonionic surfactant include a nonionic surfactant having a polyethylene glycol structure represented by a polyoxyethylene alkyl ether system.
As such a nonionic surfactant, a polyoxyethylene alkyl ether represented by the following formula (1) is preferably used.
C _n H _2n (OCH ₂ CH ₂ ) _m OH (1)
(However, n = 12-18 and m = 20-100.)

Examples of the polyoxyethylene alkyl ether represented by the above formula (1) include polyoxyethylene (23) lauryl ether (trade name: Brij L23, manufactured by Sigma Aldrich) and polyoxyethylene (20) cetyl ether (trade name). : Brij C20, manufactured by Sigma Aldrich), polyoxyethylene (20) stearyl ether (trade name: Brij S20, manufactured by Sigma Aldrich), polyoxyethylene (20) oleyl ether (trade name: Brij O20, manufactured by Sigma Aldrich) ), Polyoxyethylene (100) stearyl ether (trade name: Brij S100, manufactured by Sigma Aldrich) and the like.

Examples of nonionic surfactants include polyoxyethylene sorbitan monosteert (molecular formula: C ₆₄ H ₁₂₆ O ₂₆ , trade name: Tween 60, manufactured by Sigma Aldrich), and polyoxyethylene sorbitan trioleate (molecular formula: C ₂₄ H). ₄₄ O ₆ , trade name: Tween 85, manufactured by Sigma Aldrich, octylphenol ethoxylate (molecular formula: C ₁₄ H ₂₂ O (C ₂ H ₄ O) _n , n = 1-10, trade name: Triton X-100, Sigma Aldrich), Polyoxyethylene (40) Isooctylphenyl Ether (Molecular Formula: C ₈ H ₁₇ C ₆ H ₄₀ (CH ₂ CH ₂₀ ) ₄₀ H, Trade Name: Triton X-405, Sigma Aldrich), Poloxamer (molecular formula: C ₅ H ₁₀ O ₂ , trade name: Pluronic, manufactured by Sigma Aldrich), polyvinylpyrrolidone (molecular formula: (C ₆ H ₉ NO) _n , n = 5 to 100, manufactured by Sigma Aldrich), etc. are used. You can also do it.

The method for preparing the treatment liquid containing nanocarbon and the surfactant is not particularly limited, and a known method is used. For example, a method of ultrasonically treating a mixture of a single-walled carbon nanotube mixture and a dispersion medium containing a surfactant to disperse the single-walled carbon nanotube mixture in the dispersion medium can be mentioned.

In the cross-flow filtration method of the present embodiment, as the treatment liquid containing nanocarbon and a surfactant, for example, a single-walled carbon nanotube mixture is obtained by carrier-free electrophoresis, and a metal-type single-walled carbon nanotube and a semiconductor-type single-walled are used. It is preferable to separate into carbon nanotubes and use a treatment liquid having a relatively high content of metal-type single-walled carbon nanotubes or a treatment liquid having a relatively high content of semiconductor-type single-walled carbon nanotubes. .. In this way, a treatment liquid containing an appropriate amount of metal-type single-walled carbon nanotubes or semiconductor-type single-walled carbon nanotubes can be efficiently prepared.

In step A, the pump 40 is started to start supplying the treatment liquid 200 from the treatment liquid tank 30 to the inner tank 2 of the filter module 20, and the treatment liquid 200 is supplied to the inner tank 21 and the treatment liquid tank 30 of the filter module 20. Circulate.

While the treatment liquid 200 is circulated, the pressure of the treatment liquid 200 on the inlet side of the inner tank 21 of the filter module 20 is measured by the first pressure sensor 90. Further, while the treatment liquid 200 is circulated, the pressure of the treatment liquid 200 at the outlet side of the inner tank 21 of the filter module 20 is measured by the second pressure sensor 100. Further, the pressure of the permeating liquid 220 that has passed through the semipermeable membrane 23 on the discharge port 24 side of the outer tank 22 of the filter module 20 is measured by the third pressure sensor 110.

A pressure regulator based on the measurement results of the pressure of the processing liquid 200 in the first pressure sensor 90, the pressure of the processing liquid 200 in the second pressure sensor 100, and the pressure of the permeated liquid 220 in the third pressure sensor 110. At 50, the pressure of the treatment liquid 200 and the pressure of the permeate liquid 220 are adjusted so that the pressure of the treatment liquid 200 passing through the inner tank 21 of the filter module 20 becomes a predetermined constant pressure.

Further, in the cross-flow filtration method of the present embodiment, the pressure of the processing liquid 200 in the first pressure sensor 90, the pressure of the processing liquid 200 in the second pressure sensor 100, and the permeated liquid 220 in the third pressure sensor 110 It is preferable to have a step (hereinafter, referred to as “step C”) of adjusting the supply amount of the treatment liquid 200 to the inner tank 21 of the filter module 20 by the pump 40 based on the measurement result of the pressure of. .. Normally, the processing pressure is adjusted by operating the pressure regulator 50, but when the adjustment range of the pressure regulator 50 is exceeded, or a sudden pressure change that cannot be handled by the pressure regulator 50 occurs. In this case, the supply of the treatment liquid 200 to the inner tank 21 of the filter module 20 by the pump 40 is temporarily stopped to prevent the semipermeable membrane 23 from being damaged due to excessive pressure.

When the above steps A and C are continued, among the components contained in the treatment liquid 200, the components smaller than the pore diameter of the semipermeable membrane 23 such as the molecules of the surfactant gradually gradually become the semipermeable membrane 23 together with the dispersion medium. Permeates into the outer tank 22 of the filter module 20. It has magnitude component than the pore size of the semipermeable membrane 23, such as nano-carbon remains in the inner tank 21 of the filter module 20.
In the cross-flow filtration method of the present embodiment, the dispersion medium containing the component that has permeated the semipermeable membrane 23 is the permeate liquid 220. In the cross-flow filtration method of the present embodiment, the permeate 220 contains the above-mentioned surfactant and the above-mentioned dispersion medium.

Further, the permeated liquid 220 that has permeated into the outer tank 22 of the filter module 20 is discharged from the outer tank 22 to the permeated liquid tank 120 via the discharge port 24.

In this way, when the permeate 220 is discharged from the outer tank 22 of the filter module 20 to the permeate tank 120, the amount of the treatment liquid 200 circulating in the inner tank 21 and the treatment liquid tank 30 of the filter module 20 is reduced. As described above, since the treatment liquid tank 30 has airtightness, when the amount of the treatment liquid 200 circulating in the inner tank 21 of the filter module 20 and the treatment liquid tank 30 decreases, the pressure in the treatment liquid tank 30 decreases. Then, the replenisher liquid 210 is automatically supplied (replenished) from the replenisher liquid tank 60 to the treatment liquid tank 30. As a result, the amount of the treatment liquid 200 circulating in the inner tank 21 and the treatment liquid tank 30 of the filter module 20 is kept constant.

In the cross-flow filtration method of the present embodiment, the above-mentioned dispersion medium is used as the replenisher liquid 210. Therefore, when the replenisher liquid 210 is supplied from the replenisher liquid tank 60 to the treatment liquid tank 30, the content of the surfactant with respect to the nanocarbon in the treatment liquid 200 is relatively reduced.

In step B, the end of circulation of the treatment liquid 200 is determined based on the measurement result of the amount of the replenishment liquid 210 supplied from the replenishment liquid tank 60 to the treatment liquid tank 30.
In step B, the replenisher liquid measuring unit 80 measures the amount of the replenisher liquid 210 supplied from the replenisher liquid tank 60 to the treatment liquid tank 30. The replenishment liquid measuring unit 80 measures the liquid amount of the replenishing liquid 210 in the replenishing liquid tank 60 and the change (flow velocity) of the liquid amount of the replenishing liquid tank 60 per unit time. The end of circulation of the treatment liquid 200 is determined based on the measurement result of the liquid amount of the replenisher liquid 210. Then, the pump 40 is stopped, and the circulation of the treatment liquid 200 to the inner tank 21 and the treatment liquid tank 30 of the filter module 20 is terminated. That is, in step B, when the flow velocity of the replenisher liquid 210 reaches a predetermined value, it is determined to end the circulation of the treatment liquid 200, and after a predetermined overtreatment time has elapsed, the pump 40 is stopped and the filter module 20 The circulation of the treatment liquid 200 to the inner tank 21 and the treatment liquid tank 30 is completed. The default value of the flow velocity of the replenisher liquid 210 is a value at which the content of the surfactant in the treatment liquid 200 becomes the target amount. The overtreatment time is an additional treatment time for ensuring that the content of the surfactant in the treatment liquid 200 is equal to or less than a predetermined concentration. The overtreatment time is set so that the content of the surfactant in the treatment liquid 200 does not fall below the lower limit of the permissible amount.

The treatment liquid 200 obtained by terminating the circulation of the treatment liquid 200 has a target amount of nanocarbon and a surfactant.
Further, in the cross-flow filtration device of the present invention, the replenishment liquid measuring unit 80 measures the amount of the replenishing liquid 210 in the replenishing liquid tank 60. In the cross-flow filtration process, the liquid volume of the replenisher 210 is reduced. If the amount of the replenisher liquid 210 prepared at the start of the treatment is not sufficient, the replenisher liquid 210 may be depleted during the treatment, and as a result, the treatment liquid 200 may be depleted. In the cross-flow filtration device of the present invention, by measuring the amount of the replenisher liquid 210, when the remaining amount of the replenisher liquid 210 becomes extremely low, the pump 40 is stopped, and the inner tank 21 of the filter module 20 and the treatment are performed. The circulation of the treatment liquid 200 to the liquid tank 30 can be temporarily stopped to prevent the above-mentioned failure.

Further, in the cross-flow filtration method of the present embodiment, the end of the circulation of the processing liquid 200 is determined based on the measurement result of the liquid amount of the permeated liquid 220 in the permeated liquid measuring unit 130, the pump 40 is stopped, and the filter is filtered. The circulation of the treatment liquid 200 to the inner tank 21 and the treatment liquid tank 30 of the module 20 may be terminated. The permeate measuring unit 130 measures the amount of the permeated liquid 220 discharged from the discharge port 24 of the filter module 20. The permeate measuring unit 130 measures the amount of the permeated liquid 220 in the permeated liquid tank 120 and the change (flow velocity) of the liquid amount of the permeated liquid tank 120 per unit time. When the flow velocity of the permeate 220 reaches a predetermined value, the permeate measuring unit 130 determines the end of the circulation of the treatment liquid 200, stops the pump 40 after a predetermined overtreatment time elapses, and stops the filter module 20. The circulation of the treatment liquid 200 to the inner tank 21 and the treatment liquid tank 30 of the above is completed. The default value of the flow velocity of the permeate liquid 220 is a value at which the content of the surfactant in the treatment liquid 200 becomes the target amount. The overtreatment time is an additional treatment time for ensuring that the content of the surfactant in the treatment liquid 200 is equal to or less than a predetermined concentration. The overtreatment time is set so that the content of the surfactant in the treatment liquid 200 does not fall below the lower limit of the permissible amount.

Further, in the cross-flow filtration method of the present embodiment, in step B, the measurement result of the intermembrane pressure (TMP) between the inner tank 21 and the outer tank 22 of the filter module 20 defined by the following formula (1) is obtained. Based on this, the flow velocity of the replenisher liquid 210 is corrected, and the end of the circulation of the treatment liquid 200 is determined based on the measurement result of the flow velocity of the replenisher liquid 210 obtained by the correction.
TMP = (P _f + _Pr ) /2-P _p ... (1)
(However, TMP is the intermembrane pressure (TMP) between the inner tank 21 and the outer tank 22 of the _{filter module 20, P f} is the pressure of the treatment liquid 200 on the inlet side of the inner tank 21 of the filter module 20, and _Pr is the filter. the pressure of the treatment liquid 200 at the outlet side of the inner tank 21 of the module 20, _{P p} represents the pressure in the permeate 220 at the discharge port 24 side of the outer tub 22 of the filter module 20.)

That is, when the flow velocity of the replenisher liquid 210 obtained by the correction reaches a predetermined value, it is determined to end the circulation of the treatment liquid 200, and after a predetermined overtreatment time has elapsed, the pump 40 is stopped and the filter module 20 The circulation of the treatment liquid 200 to the inner tank 21 and the treatment liquid tank 30 of the above is completed.
Further, here, the case where the replenisher flow velocity is corrected by the intermembrane pressure (TMP) calculated from the above formula (1) is described, but the pressure (P _f ) on the inlet side of the inner tank 21 or the pressure (P f) or The effect is the same even if the replenisher flow rate is corrected by using the average value of the pressure _{(P f} ) on the inlet side and the pressure (P _r ) on the outlet side of the inner tank 21.

Further, in the cross-flow filtration method of the present embodiment, in step B, the measurement result of the intermembrane pressure (TMP) between the inner tank 21 and the outer tank 22 of the filter module 20 defined by the above formula (1) is obtained. Based on this, the flow velocity of the permeate 220 may be corrected, and the end of the circulation of the treatment liquid 200 may be determined based on the measurement result of the flow velocity of the permeate 220 obtained by the correction.

That is, when the flow velocity of the permeate 220 obtained by the correction reaches a predetermined value, it is determined to end the circulation of the treatment liquid 200, and after a predetermined overtreatment time has elapsed, the pump 40 is stopped and the filter module 20 is stopped. The circulation of the treatment liquid 200 to the inner tank 21 and the treatment liquid tank 30 of the above is completed.
Further, here, the case where the permeate flow velocity is corrected by the intermembrane pressure (TMP) calculated from the above formula (1) is described, but the pressure (P _f ) on the inlet side of the inner tank 21 or the pressure (P f) or The effect is the same even if the permeate flow velocity is corrected by using the average value of the pressure _{(P f} ) on the inlet side and the pressure (P _r ) on the outlet side of the inner tank 21.

According to the cross-flow filtration method using the cross-flow filtration device 10 of the present embodiment, it is possible to efficiently determine the end of the removal treatment in the removal treatment of the excess surfactant contained in the treatment liquid 200. .. Further, according to the cross-flow filtration method using the cross-flow filtration device 10 of the present embodiment, a treatment liquid in which the contents of nanocarbon and the surfactant are adjusted to the desired amounts with high accuracy can be obtained.

In the cross-flow filtration method of the present embodiment, the case where the treatment liquid 200 contains nanocarbon, a surfactant, and a dispersion medium is illustrated, but the cross-flow filtration method of the present embodiment is not limited to this. .. The cross-flow filtration method of the present embodiment can also be applied to the concentration of proteins and cells and the production of pure water.

[Second Embodiment]
(Cross flow filtration device)
FIG. 4 is a schematic view showing the cross-flow filtration device of the present embodiment. In FIG. 4, the same components as those of the cross-flow filtration device of the first embodiment shown in FIG. 1 are designated by the same reference numerals, and redundant description will be omitted.
The cross-flow filtration device 300 of the present embodiment includes a filter module 20, a treatment liquid tank 30, a pump 40, a pressure regulator 50, a replenishment liquid tank 60, a control unit 70, a replenishment liquid measurement unit 80, and the like. A first pressure sensor 90 (P _f ), a second pressure sensor 100 (P _r ), and a third pressure sensor 110 (P _p ) are provided. Further, the cross-flow filtration device 300 of the present embodiment may include a permeation liquid tank 120 and a permeation liquid measurement unit 130.

In the cross-flow filtration device 300 of the present embodiment, similarly to the cross-flow filtration device 10 of the first embodiment, the amount of the permeated liquid 220 discharged from the filter module 20 and the amount of the permeate liquid 220 discharged from the replenishment liquid tank 60 to the treatment liquid tank 30. The amount of replenishment liquid 210 replenished becomes equal. Further, the amount of the permeate 220 per unit time (flow rate of the permeate 220) and the amount of the replenisher 210 per unit time (flow rate of the replenisher 210) are also substantially equal.

The control unit 70 is electrically connected to the replenisher liquid measuring unit 80 via a cable 153.
Further, the control unit 70 is electrically connected to the permeate measuring unit 130 via a cable 157.

The replenishing liquid measuring unit 80 is a flow meter for measuring the flow rate of the replenishing liquid 210 supplied from the replenishing liquid tank 60 to the processing liquid tank 30. In the present embodiment, the replenisher liquid measuring unit 80 is also referred to as a first flow meter 310. The first flow meter 310 measures the flow rate (flow velocity) of the replenishing liquid 210 supplied from the replenishing liquid tank 60 to the processing liquid tank 30 per unit time.
The first flow meter 310 is provided in the middle of the third pipe 143.

The permeation liquid measuring unit 130 is a flow meter for measuring the flow rate of the permeation liquid 220 discharged from the discharge port 24. In the present embodiment, the permeate measuring unit 130 is also referred to as a second flow meter 320. The second flow meter 320 measures the flow rate (flow velocity) of the permeate 220 discharged from the discharge port 24 per unit time.
The second flow meter 320 is provided in the middle of the fourth pipe 144.

The first flow meter 310 and the second flow meter 320 are not particularly limited, and examples thereof include a flow meter that measures the flow rate of a general liquid.

According to the cross-flow filtration device 300 of the present embodiment, for example, the cross-flow filtration method described later can be carried out, and in the removal treatment of the excess surfactant contained in the treatment liquid 200, the removal treatment is performed. The end can be determined efficiently. Further, according to the cross-flow filtration device 300 of the present embodiment, for example, the cross-flow filtration method described later can be implemented, and the content of nanocarbon and the surfactant can be adjusted to the target amount with high accuracy. A adjusted treatment solution is obtained.

[Cross-flow filtration method]
The cross-flow filtration method using the cross-flow filtration device 300 will be described with reference to FIG. 4, and the operation of the cross-flow filtration device 300 will be described.

The cross-flow filtration method of the present embodiment includes a step (step A) of circulating the treatment liquid 200 to the inner tank 21 and the treatment liquid tank 30 of the filter module 20, and replenishment supplied from the replenishment liquid tank 60 to the treatment liquid tank 30. It has a step (step B) of determining the end of circulation of the treatment liquid 200 according to the amount of the liquid.

In step A, the pump 40 is started to start supplying the processing liquid 200 from the processing liquid tank 30 to the inner tank 21 of the filter module 20, and the filter module 20 is started in the same manner as in the cross-flow filtration method of the first embodiment. The treatment liquid 200 is circulated to the inner tank 21 and the treatment liquid tank 30 of the above.

Further, the cross-flow filtration method of the present embodiment is the same as the cross-flow filtration method of the first embodiment, in that the pressure of the treatment liquid 200 in the first pressure sensor 90 and the treatment liquid 200 in the second pressure sensor 100 A step (step C) of adjusting the supply amount of the processing liquid 200 to the inner tank 21 of the filter module 20 by the pump 40 based on the pressure and the measurement result of the pressure of the permeated liquid 220 by the third pressure sensor 110. It is preferable to have it.

When the above steps A and C are continued, among the components contained in the treatment liquid 200, the components smaller than the pore diameter of the semipermeable membrane 23 gradually permeate through the semipermeable membrane 23 together with the dispersion medium, and the filter module. It penetrates into the outer tank 22 of 20.
In the cross-flow filtration method of the present embodiment, the dispersion medium containing the component that has permeated the semipermeable membrane 23 is the permeate liquid 220. In the cross-flow filtration method of the present embodiment, the permeate 220 contains the above-mentioned surfactant and the above-mentioned dispersion medium.

Further, the permeated liquid 220 that has permeated into the outer tank 22 of the filter module 20 is discharged from the outer tank 22 to the permeated liquid tank 120 via the discharge port 24.

Further, in the cross-flow filtration method of the present embodiment, the replenisher liquid 210 is automatically supplied (replenished) from the replenisher liquid tank 60 to the treatment liquid tank 30 as in the cross-flow filtration method of the first embodiment. .. As a result, the amount of the treatment liquid 200 circulating in the inner tank 21 and the treatment liquid tank 30 of the filter module 20 is kept constant.

In step B, it is preferable to determine the end of circulation of the treatment liquid 200 based on the measurement result of the flow rate of the replenishment liquid 210 supplied from the replenishment liquid tank 60 to the treatment liquid tank 30.
In step B, the flow velocity of the replenisher liquid 210 supplied from the replenisher liquid tank 60 to the treatment liquid tank 30 is measured by the first flow meter 310. The end of circulation of the treatment liquid 200 is determined based on the measurement result of the flow velocity of the replenisher liquid 210. Then, the pump 40 is stopped to end the circulation of the treatment liquid 200 to the inner tank 21 and the treatment liquid tank 30 of the filter module 20. That is, in step B, when the flow velocity of the replenisher liquid 210 reaches a predetermined value, it is determined to end the circulation of the treatment liquid 200, and after a predetermined overtreatment time has elapsed, the pump 40 is stopped and the filter module 20 The circulation of the treatment liquid 200 to the inner tank 21 and the treatment liquid tank 30 is completed. The default value of the flow velocity of the replenisher liquid 210 is a value at which the content of the surfactant in the treatment liquid 200 becomes the target amount. The overtreatment time is an additional treatment time for ensuring that the content of the surfactant in the treatment liquid 200 is equal to or less than a predetermined concentration. The overtreatment time is set so that the content of the surfactant in the treatment liquid 200 does not fall below the lower limit of the permissible amount.

The treatment liquid 200 obtained by terminating the circulation of the treatment liquid 200 has a target amount of nanocarbon and a surfactant.

Further, in the cross-flow filtration method of the present embodiment, the end of the circulation of the treatment liquid 200 is determined based on the measurement result of the flow rate of the permeate liquid 220 in the second flow meter 320, the pump 40 is stopped, and the filter is filtered. The circulation of the treatment liquid 200 to the inner tank 21 and the treatment liquid tank 30 of the module 20 may be terminated. The second flow meter 320 measures the flow velocity of the permeate 220 discharged from the discharge port 24 of the filter module 20. In the second flow meter 320, when the flow velocity of the permeate 220 reaches a predetermined value, it is determined to end the circulation of the treatment liquid 200, and after a predetermined overtreatment time has elapsed, the pump 40 is stopped and the filter module is used. The circulation of the treatment liquid 200 to the inner tank 21 and the treatment liquid tank 30 of 20 is completed. The default value of the flow velocity of the permeate liquid 220 is a value at which the content of the surfactant in the treatment liquid 200 becomes the target amount. The overtreatment time is an additional treatment time for ensuring that the content of the surfactant in the treatment liquid 200 is equal to or less than a predetermined concentration. The overtreatment time is set so that the content of the surfactant in the treatment liquid 200 does not fall below the lower limit of the permissible amount.

Further, in the cross-flow filtration method of the present embodiment, in step B, the measurement result of the intermembrane pressure (TMP) between the inner tank 21 and the outer tank 22 of the filter module 20 defined by the following formula (1) is obtained. Based on this, it is preferable to correct the flow velocity of the replenisher liquid 210 and end the circulation of the treatment liquid 200 based on the measurement result of the flow velocity of the replenisher liquid 210 obtained by the correction.
TMP = (P _f + _Pr ) /2-P _p ... (1)
(However, TMP is the intermembrane pressure (TMP) between the inner tank 21 and the outer tank 22 of the _{filter module 20, P f} is the pressure of the treatment liquid 200 on the inlet side of the inner tank 21 of the filter module 20, and _Pr is the filter. the pressure of the treatment liquid 200 at the outlet side of the inner tank 21 of the module 20, _{P p} represents the pressure in the permeate 220 at the discharge port 24 side of the outer tub 22 of the filter module 20.)

That is, when the flow velocity of the replenisher liquid 210 obtained by the correction reaches a predetermined value, it is determined to end the circulation of the treatment liquid 200, and after a predetermined overtreatment time has elapsed, the pump 40 is stopped and the filter module 20 The circulation of the treatment liquid 200 to the inner tank 21 and the treatment liquid tank 30 of the above is completed.
Further, here, the case where the replenisher flow velocity is corrected by the intermembrane pressure (TMP) calculated from the above formula (1) is described, but the pressure (P _f ) on the inlet side of the inner tank 21 or the pressure (P f) or The effect is the same even if the replenisher flow rate is corrected by using the average value of the pressure _{(P f} ) on the inlet side and the pressure (P _r ) on the outlet side of the inner tank 21.

Further, in the cross-flow filtration method of the present embodiment, in step B, the measurement result of the intermembrane pressure (TMP) between the inner tank 21 and the outer tank 22 of the filter module 20 defined by the above formula (1) is obtained. Based on this, the flow velocity of the permeate 220 may be corrected, and the end of the circulation of the treatment liquid 200 may be determined based on the measurement result of the flow velocity of the permeate 220 obtained by the correction.

That is, when the flow velocity of the permeate 220 obtained by the correction reaches a predetermined value, it is determined to end the circulation of the treatment liquid 200, and after a predetermined overtreatment time has elapsed, the pump 40 is stopped and the filter module 20 is stopped. The circulation of the treatment liquid 200 to the inner tank 21 and the treatment liquid tank 30 of the above is completed.
Further, here, the case where the permeate flow velocity is corrected by the intermembrane pressure (TMP) calculated from the above formula (1) is described, but the pressure (P _f ) on the inlet side of the inner tank 21 or the pressure (P f) or The effect is the same even if the permeate flow velocity is corrected by using the average value of the pressure _{(P f} ) on the inlet side and the pressure (P _r ) on the outlet side of the inner tank 21.

According to the cross-flow filtration method using the cross-flow filtration device 300 of the present embodiment, it is possible to efficiently determine the end of the removal treatment in the removal treatment of the excess surfactant contained in the treatment liquid 200. .. Further, according to the cross-flow filtration method using the cross-flow filtration device 300 of the present embodiment, a treatment liquid in which the contents of nanocarbon and the surfactant are adjusted to the desired amounts with high accuracy can be obtained.

In the cross-flow filtration method of the present embodiment, the case where the treatment liquid 200 contains nanocarbon, a surfactant, and a dispersion medium is illustrated, but the cross-flow filtration method of the present embodiment is not limited to this. .. The cross-flow filtration method of the present embodiment can also be applied to the concentration of proteins and cells and the production of pure water.

FIG. 5 shows a flowchart showing the cross-flow filtration method of the present invention.

Hereinafter, the present invention will be described in more detail with reference to Experimental Examples, but the present invention is not limited to the following Experimental Examples.

[Experimental Example 1]
Solution A1, 0.1 wt% of polyoxyethylene (100) stearyl ether (trade name: Brij S100, manufactured by Sigma Aldrich), which is a nonionic surfactant, dissolved in pure water (water) in an amount of 0.01 wt%. Solution B1 and solution C1 in which 2 wt% was dissolved were prepared.
The amount of solution A1, solution B1 and solution C1 was 20 mL.
Using the cross-flow filtration device 10 shown in FIG. 1, cross-flow filtration treatment of solution A1, solution B1 and solution C1 was performed.
As the filter module 20, a module provided with a semipermeable membrane 23 having a pore diameter of 750 kDa and an area of 20 cm ^{2 was used.}
_{The pressure (P f} ) of the solution A1, the solution B1 and the solution C1 on the inlet side of the inner tank 21 of the filter module 20 was set to 20 kPa.
Pure water was used as the replenisher.
In this cross-flow filtration treatment, the consumption of the replenisher was measured with the lapse of the treatment time. The results are shown in FIG.

From the results of FIG. 6, it was confirmed that the slope of the consumption amount of the replenisher increased with the lapse of the treatment time.
Further, the consumption amount of the replenisher solution per unit time was obtained from the consumption amount of the replenisher solution shown in FIG. 6, and the flow rate of the replenisher solution was calculated. The relationship between the treatment time and the flow rate of the replenisher is shown in FIG.
From the results shown in FIG. 7, when the solution C1 (2 wt% aqueous solution containing Brij S100) was used, the flow rate of the replenisher immediately after the start of the treatment was about 0.5 g / m, and as the treatment time elapsed, the flow rate of the replenisher was about 0.5 g / m. It was confirmed that the flow rate of the replenisher solution increased. Further, when the solution B1 (Aqueous solution having a content of Brij S100 of 0.1 wt%) was used, the flow rate of the replenisher immediately after the start of the treatment was about 1.5 g / m, and the replenisher was replenished with the lapse of the treatment time. It was confirmed that the flow velocity increased. Further, when the solution A1 (Aqueous solution having a content of Brij S100 of 0.01 wt%) was used, the flow rate of the replenisher immediately after the start of the treatment was about 2.1 g / m, and the replenisher was replenished with the lapse of the treatment time. It was confirmed that the flow velocity increased. From the above results, it was found that as the content of the nonionic surfactant in the solution decreased, the flow rate of the replenisher immediately after the start of the treatment increased.
Next, the graph showing the relationship between the replenisher flow rate and the treatment time when the solution A1 is used is offset by 23.5 hours, and the graph showing the relationship between the replenisher flow rate and the treatment time when the solution B1 is used is shown. When illustrated with an 18-hour offset, it was found that the three graphs almost overlapped, as shown in FIG.

The flow velocity of the permeated liquid containing the nonionic surfactant (Brij S100) that permeates the semipermeable membrane 23 of the filter module 20 largely depends on the pressure (applied pressure) applied to the semipermeable membrane 23. Further, since the semipermeable membrane 23 has an osmotic pressure (π = CRT) in the opposite direction according to the number of particles inside the semipermeable membrane 23 (the number of nonionic surfactant particles), the semipermeable membrane 23 is semipermeable. The effective pressure applied to the membrane 23 is the difference between the applied pressure and the osmotic pressure (see FIG. 9).
For example, in solution C1 (Aqueous solution containing 2 wt% of Brij S100), the osmotic pressure at T = 300K was calculated to be 10.6 kPa from the above formula when all the molecules contributed to the osmotic pressure. Here, R = 8.31 × 10 ³ L · Pa / K · mol, C = 4.3 mM mol / L (2 wt% Brij S100). Therefore, when the molecular concentration of Brij S100 inside the semipermeable membrane 23 is high, the effective pressure applied to the semipermeable membrane 23 is reduced by the osmotic pressure, and the surfactant molecule is a dispersion medium (pure water). At the same time, the speed at which the filter module 20 is discharged from the inner tank 21 to the outer tank 22 becomes slower. On the other hand, when the molecular concentration of Brij S100 inside the semipermeable membrane 23 is low, the effective pressure applied to the semipermeable membrane 23 increases, and the surfactant molecules are contained together with the dispersion medium in the inner tank 21 of the filter module 20. Is easily discharged from the outer tank 22 to the outer tank 22, and the flow velocity of the permeated liquid becomes large.
Therefore, knowing the permeate flow velocity is the same as knowing the particle concentration in the treatment solution, and by accurately measuring and calculating the permeate flow velocity, it is possible to accurately know the concentration of the surfactant in the solution. Can be done.
Further, in the cross-flow filtration device of the present invention, the permeate amount and the replenisher amount are equal, and the permeate amount per unit time (permeate flow rate) and the replenisher amount per unit time (replenisher flow rate) are also the same. Therefore, the change in the permeate flow rate due to the change in osmotic pressure could be detected as the change in the replenisher flow rate. As a result, the concentration of the surfactant in the solution can be accurately known by accurately measuring and calculating the flow velocity of the replenisher.

The graph showing the relationship between the treatment time and the flow rate of the replenisher shown in FIG. 8 shows the concentration dependence of Brij S100 inside the semipermeable membrane 23. The effective pressure applied to the semipermeable membrane 23, that is, the flow rate of the replenisher liquid, depends on the molecular concentration of the solution inside the filter module 20. Therefore, from FIG. 8, the solution C1 (2 wt% aqueous solution containing Brij S100) was cross-flow filtered, and 18 hours after the replenisher flow rate became about 1.5 g / m, the solution inside the filter module 20 was formed. The content of Brij S100 in the above is about 0.1 wt%, which is about the same as that of the solution B1. Further, after 23.5 hours when the replenisher flow rate is about 2.1 g / m, the content of Brij S100 in the solution inside the filter module 20 is about 0.01 wt%, which is about the same as the solution C1. I understand.

According to the above cross-flow filtration treatment, if the circulating flow velocity of the solution, the applied pressure to the solution, the pore diameter of the semipermeable membrane 23, the area of the semipermeable membrane 23, and the volume of the filter module 20 are equal, the replenisher flow velocity is equal. It does not depend on the concentration of the surfactant at the start of the treatment and the volume of the treatment liquid to be treated, and reflects only the molecular concentration of the solution inside the filter module 20. Therefore, in the cross-flow filtration treatment under the predetermined conditions, the residual concentration of the surfactant can be known by measuring the flow rate of the replenisher, and the surfactant can be removed with high accuracy.

[Experimental Example 2]
A solution B2 in which 0.1 wt% of polyoxyethylene (100) stearyl ether (trade name: Brij S100, manufactured by Sigma-Aldrich), which is a nonionic surfactant, was dissolved in pure water was prepared. The amount of solution B2 was 20 mL.
Using the cross-flow filtration device 10 shown in FIG. 1, a cross-flow filtration treatment was performed on three solutions B2.
_{The pressures (P f} ) of the solution B2 on the inlet side of the inner tank 21 of the filter module 20 were set to 15 kPa, 20 kPa, and 30 kPa.
Pure water was used as the replenisher.
In this cross-flow filtration treatment, the consumption amount of the replenisher solution was measured with the lapse of the treatment time, and the consumption amount of the replenisher solution (replenishment solution flow rate) per unit time was calculated. The relationship between the treatment time and the flow rate of the replenisher is shown in FIG.

From the results of FIG. 10, the flow rate of the replenisher liquid increases as _{the pressure (P f} ) of the solution B2 on the inlet side of the inner tank 21 of the filter module 20 increases.
Here, the intermembrane pressure (TMP) between the inner tank 21 and the outer tank 22 of the filter module 20 is defined by the above equation (1). Further, the normalized replenisher flow rate is defined by the following formula (2).
Normalized replenisher flow rate = replenisher flow rate x (reference TMP / TMP during processing) ... (2)
The reference TMP is 24 kPa, which is the standard intermembrane pressure (TMP) when the _{pressure (P f} ) of the solution B2 at the inlet side of the inner tank 21 of the filter module 20 of the cross-flow filtration device 10 is 20 kPa. bottom.
The normalized replenisher flow rate is calculated using the above formula (2), and the relationship with the processing time is shown in FIG.

From the results of FIG. 11, the normalized replenisher flow velocity standardized by the intermembrane pressure (TMP) is constant regardless of the fluctuation of _{the pressure (P f) of the solution B1 on the inlet side of the inner tank 21 of the filter module 20.} It was confirmed that the value was about 1.5 g / m.

[Experimental Example 3]
A solution A2 in which 0.01 wt% of polyoxyethylene (100) stearyl ether (trade name: Brij S100, manufactured by Sigma-Aldrich), which is a nonionic surfactant, was dissolved in pure water was prepared. A cross-flow filtration treatment was performed in the same manner as in Experimental Example 2.
In this cross-flow filtration treatment, the consumption amount of the replenisher solution was measured with the lapse of the treatment time, and the consumption amount of the replenisher solution (replenishment solution flow rate) per unit time was calculated. The relationship between the treatment time and the flow rate of the replenisher is shown in FIG.

From the results of FIG. 12, the flow rate of the replenisher liquid increases as _{the pressure (P f} ) of the solution A2 on the inlet side of the inner tank 21 of the filter module 20 increases.
Further, in the same manner as in Experimental Example 2, the normalized replenisher flow rate was calculated using the above formula (2), and the relationship with the processing time is shown in FIG.

From the results of FIG. 13, the normalized replenisher flow velocity standardized by the intermembrane pressure (TMP) is constant regardless of the fluctuation of _{the pressure (P f) of the solution A1 on the inlet side of the inner tank 21 of the filter module 20.} It was confirmed that the value was about 2.1 g / m.

From the results of Experimental Example 2 and Experimental Example 3, pressure fluctuation occurred during the cross-flow filtration treatment by using the standardized replenisher flow velocity corrected by the intermembrane pressure (TMP) during the cross-flow filtration treatment. Even so, it was found that the residual concentration of the surfactant could be known and the surfactant could be removed with high accuracy. In general, the pressure regulator 50 capable of pressure control by a signal from the control unit 70 is very expensive. However, even if an inexpensive manual pinch valve is used as a pressure regulator by calculating the normalized replenisher flow velocity standardized by the intermembrane pressure (TMP) as in the present invention, even if pressure fluctuation occurs. , Surfactant can be removed with high accuracy.
Further, here, the case where the intermembrane pressure (TMP) is used to correct the replenisher flow velocity calculated from the above formula (2) is described, but instead of the intermembrane pressure (TMP), the inner tank is used. Even if the replenisher flow velocity is corrected using the average value of the pressure _{(P f} ) on the inlet side of 21 or the pressure (P _f ) on the inlet side and the pressure (P _{r) on the outlet side of the inner tank 21.} The effect is similar.

[Experimental Example 4]
A case of removing the surfactant contained in the dispersion liquid containing the single-walled carbon nanotubes (hereinafter, referred to as “single-walled carbon nanotube dispersion liquid”) will be described. The single-walled carbon nanotube dispersion liquid is one that has been subjected to ultrasonic dispersion treatment or purification treatment by ultracentrifugation, or for example, metal-type single-walled carbon nanotubes and semiconductor-type single-walled carbon nanotubes are separated by electrophoresis or the like. Can be mentioned. These single-walled carbon nanotube dispersions contain about several wt% of surfactant.
When such a single-walled carbon nanotube dispersion liquid is used for electrical applications or electronic devices, the surfactant interferes with electrical conduction. Therefore, it is necessary to remove the excess surfactant contained in the single-walled carbon nanotube dispersion liquid.

The case of Brij S100, which is one of the nonionic surfactants, will be described in detail. For example, since the critical micelle concentration (CMC) of Brij S100 is about 0.01 wt%, if the concentration of Brij S100 in the single-walled carbon nanotube dispersion is less than 0.01 wt%, the single-walled carbon nanotubes cannot be stably dispersed. Aggregates into. Therefore, the lower limit of the concentration of the nonionic surfactant in the single-walled carbon nanotube dispersion liquid is set to 0.01 wt%. On the other hand, when applying the single-walled carbon nanotubes to electronic devices, the upper limit of the concentration of the nonionic surfactant in the single-walled carbon nanotube dispersion liquid is set to 0.1 wt% so as not to interfere with electrical conduction. If the concentration of the single-walled carbon nanotube dispersion is lower than this, the Brij S100 can be sufficiently removed by precipitating the single-walled carbon nanotubes on the substrate and then washing with a solution or thermally decomposing by heat treatment. can.
For these reasons, when the single-walled carbon nanotube dispersion is used for electrical applications or electronic devices, the concentration of the nonionic surfactant in the single-walled carbon nanotube dispersion is the number of critical micelle concentrations. It needs to be doubled.

Pure water using a mixture of single-walled carbon nanotubes (eDIPS (enhanced Direct Injection Pyrolytic Synthesis) single-walled carbon nanotubes, average diameter: 1.0 nm) and Brij S100, a nonionic surfactant. Further, for example, using the method described in Patent Document 1, a dispersion liquid obtained by extracting semiconductor-type single-walled carbon nanotubes with high purity was prepared. The concentration of the nonionic surfactant contained in this semiconductor-type single-walled carbon nanotube dispersion is unknown, but the concentration of Brij S100 must be 0.1 wt% or less in order to be used for electronic devices. .. Further, in order to stably disperse the semiconductor type single-walled carbon nanotubes for a long period of time, it is necessary to maintain a concentration higher than the critical micelle concentration (CMC) of 0.01 wt% of Brij S100.
Next, solution A3, 0.1 wt%, in which 0.01 wt% of polyoxyethylene (100) stearyl ether (trade name: Brij S100, manufactured by Sigma-Aldrich), which is a nonionic surfactant, was dissolved in pure water was dissolved. Solution B3 was prepared. The amount of solution A3 and solution B3 was 20 mL.

The cross-flow filtration treatment of the solution A3 was performed using the cross-flow filtration device 10 shown in FIG. The pressure was adjusted so that the TMP calculated by the above formula (1) was 24 kPa, and the replenisher flow rate was measured. The flow rate of the replenisher at the start of the cross flow was about 2.1 g / m. This is the replenisher flow rate when the surfactant concentration is at the lower limit.
The cross-flow filtration treatment of the solution B3 was performed using the cross-flow filtration device 10 shown in FIG. The pressure was adjusted so that the TMP calculated by the above formula (1) was 24 kPa, and the replenisher flow rate was measured. The flow rate of the replenisher at the start of the cross flow was about 1.5 g / m. This is the replenisher flow rate when the surfactant concentration is at the upper limit.
Next, a cross-flow filtration treatment of the semiconductor-type single-walled carbon nanotube dispersion liquid having an unknown surfactant concentration was performed.
The replenisher flow rate of 1.7 g / m, which is between the replenisher flow rates of the solution A3 and the solution B3, was set to the threshold flow rate, and the overtreatment time was set to 60 minutes, and the cross-flow filtration treatment was performed.
In this treatment for removing the nonionic surfactant, the flow rate (cumulative) of the replenisher was measured with the lapse of the treatment time, and the flow rate of the replenisher was calculated. In addition, the pressure during processing was measured, and the intermembrane pressure (TMP) was calculated using the above formula (1). Further, using the above formula (2), the reference TMP was set to 24 kPa, and the standardized replenisher flow rate was calculated from the replenisher flow rate and the intermembrane pressure (TMP). The time when the normalized replenisher flow rate exceeded the threshold flow rate was integrated, and when the integrated time reached the overtreatment time of 60 minutes, the cross-flow filtration process was stopped. The relationship between the treatment time and the normalized replenisher flow rate was calculated. The results are shown in FIG.

The flow rate of the normalized replenisher fluctuates finely due to short-period pressure fluctuations due to the pulsation of the pump 40. Therefore, in order for the integrated time exceeding the threshold flow velocity to reach the 60 minutes set by the overprocessing time, a processing time longer than 60 minutes is required. The flow rate of the standardized replenisher at the end of the treatment is sufficiently larger than about 1.5 g / m at the target upper limit of 0.1 wt% and about 2.1 g / m at the lower limit of 0.01 wt%. Smaller than enough.
Further, the absorbance of the treated single-walled carbon nanotube dispersion was measured using a spectrophotometer (trade name: ultraviolet visible near infrared spectrophotometer UV-3600, manufactured by Shimadzu Corporation).
The results are shown in FIG. It is generally known that when single-walled carbon nanotubes aggregate, the steep peaks observed in absorbance are blunted.

From the results of FIG. 15, in the single-walled carbon nanotube dispersion liquid, no trace of agglomeration of the single-walled carbon nanotubes was observed before and after the cross-flow filtration treatment, and the monodispersity of the single-walled carbon nanotubes was maintained. It was confirmed that.
In addition, the concentration of the surfactant, Brij S100, in the treated single-walled carbon nanotube dispersion was examined. The concentration of Brij S100 in the single-walled carbon nanotube dispersion liquid can be obtained by analyzing the refractive index and the absorbance in detail. The result was 0.029 wt%. A semiconductor-type single-walled carbon nanotube dispersion having the desired surfactant concentration was obtained.
A thin film transistor was prototyped using the semiconductor-type single-walled carbon nanotube dispersion liquid obtained above as a CNT ink. First, a gate electrode, a gate insulating film, and a source / drain electrode were formed on a plastic substrate. CNT ink was dropped between the source and drain electrodes and dried. The Brij S100 remaining on the substrate was removed by washing with a solution and heat treatment. FIG. 16 shows the transmission characteristics of the manufactured thin film transistor. Good characteristics were obtained with an on / off current ratio of 5 digits or more and a field effect mobility of 4.7 cm2 / Vs. With the cross-flow filtration device and the cross-flow filtration method of the present invention, it was possible to reduce the excessive concentration of the surfactant in the semiconductor-type single-walled carbon nanotube dispersion liquid. As a result, it was possible to prevent the surfactant from interfering with electrical conduction and to obtain a good special thin film transistor.

[Experimental Example 5]
A mixture of single-walled carbon nanotubes (eDIPS (enhanced Direct Injection Pyrolytic Synthesis) was dispersed in pure water using a nonionic surfactant, Brij S100, and further, for example, in Patent Document 1. Seven types of dispersions obtained by extracting high-purity semiconductor-type single-walled carbon nanotubes were prepared using the method described. The concentration of the nonionic surfactant contained in these semiconductor-type single-walled carbon nanotube dispersions was It is unknown.
Using the cross-flow filtration device 10 shown in FIG. 1, the cross-flow filtration treatment of each solution was performed in the same manner as in Experimental Example 4.
Table 1 summarizes the starting liquid volume of each solution, the time required for the treatment, and the concentration of Brij S100 after the treatment. The time required for the treatment depends on the amount of liquid at the start or the concentration (unknown) of Brij S100 at the start. However, by using the cross-flow filtration device and the cross-flow filtration method of the present invention, it was possible to obtain a dispersion having good reproducibility and a desired surfactant concentration regardless of the initial state of the treatment solution.
Further, by using the semiconductor type single-walled carbon nanotube dispersion liquid subjected to these treatments as the CNT ink, it was possible to obtain a thin film transistor having excellent characteristics as in Experimental Example 4.
Further, in the cross-flow filtration device of the present invention, if a valve or the like is added in the middle of the third pipe 143 that connects the injection pipe 33 of the treatment liquid tank 30 and the suction pipe 61 of the replenishment liquid tank 60. It is possible to temporarily maintain the pressure inside the treatment liquid tank 30 at atmospheric pressure. When the pressure inside the treatment liquid tank 30 is maintained at atmospheric pressure, the replenisher liquid 210 is not replenished even if the treatment liquid 200 in the treatment liquid tank 30 decreases, and as a result, the single-walled carbon nanotubes of the treatment liquid 200 and the surface activity The agent can be concentrated. When the single-walled carbon nanotubes of the treatment liquid 200 have a lower concentration than the intended use, they can be concentrated by the above means. After concentrating to the desired single-walled carbon nanotube concentration, the overconcentrated surfactant can be removed by closing the valve loaded on the third tube 143 and continuing the treatment.

The cross-flow filtration device and the cross-flow filtration method of the present invention can efficiently determine the end of the removal treatment in the removal treatment of excess components contained in the treatment liquid.

Some or all of the above embodiments may also be described, but not limited to:

(Appendix 1) A filter module having an inner tank and an outer tank separated by a semi-transparent film, a treatment liquid tank for accommodating the treatment liquid, and the treatment liquid circulated to the inner tank and the treatment liquid tank of the filter module. A pump for charging, a replenisher tank for accommodating the replenisher liquid to be replenished in the treatment liquid tank, at least one or more sensors for measuring the pressure of the circulating treatment liquid, and the replenishment liquid tank to the treatment liquid tank. A cross-flow filtration device comprising a replenishment liquid measuring unit for measuring the amount of the replenishment liquid to be supplied, and the replenishment liquid is continuously replenished to the treatment liquid tank.

(Appendix 2) The cross-flow filtration device according to Appendix 1, further comprising a control unit that controls the circulation amount of the treatment liquid from the treatment liquid tank to the inner tank by the pump based on the amount of the replenishment liquid.

(Appendix 3) The cross-flow filtration device according to Appendix 1 or Appendix 2, wherein the replenisher liquid measuring unit measures the flow velocity of the replenisher liquid supplied from the replenisher liquid tank to the treatment liquid tank.

(Appendix 4) The cross-flow filtration device according to Appendix 3, further comprising a control unit that controls the circulation amount of the treatment liquid from the treatment liquid tank to the inner tank by the pump based on the flow rate of the replenishment liquid.

(Appendix 5) The cross-flow filtration device according to Appendix 1 or Appendix 2, which is provided with a permeation liquid measuring unit at the outlet of the outer layer and measures the flow velocity of the permeate.

(Appendix 6) The cross-flow filtration device according to Appendix 5, further comprising a control unit that controls the circulation amount of the treatment liquid from the treatment liquid tank to the inner tank by the pump based on the flow rate of the permeated liquid.

(Appendix 7) A cross-flow filtration method using the cross-flow filtration device according to any one of Appendix 1 to 6, wherein the treatment liquid is circulated to the inner tank and the treatment liquid tank, and the above-mentioned. A cross-flow filtration method comprising a step of determining the end of circulation of the treatment liquid according to the amount of the replenishing liquid in the replenishing liquid tank.

(Appendix 8) The pressure of the treatment liquid on the inlet side of the inner tank, the pressure of the treatment liquid on the outlet side of the inner tank, and the permeate liquid that has permeated the semipermeable membrane on the discharge port side of the outer tank. 7. The cross-flow filtration method according to Appendix 7, which comprises a step of adjusting the circulation amount of the treatment liquid to the inner tank based on the pressure of the above.

(Appendix 9) In the step of determining the end of the circulation of the treatment liquid, the end of the circulation of the treatment liquid is terminated based on the measurement result of the flow velocity of the replenisher liquid supplied from the replenishment liquid tank to the treatment liquid tank. The cross-flow filtration method according to Appendix 7 and Appendix 8 to be determined.

(Appendix 10) In the step of determining the end of circulation of the treatment liquid, the flow velocity of the replenisher is corrected based on the measurement result of the pressure of the circulating treatment liquid, and the replenisher obtained by the correction is corrected. The cross-flow filtration method according to Appendix 9, which determines the end of circulation of the treatment liquid based on the measurement result of the flow velocity.

(Appendix 11) The cross-flow filtration method according to Appendix 8, which determines the end of circulation of the treatment liquid based on the measurement result of the flow velocity of the permeated liquid.

(Appendix 12) The flow velocity of the permeated liquid is corrected based on the measurement result of the pressure of the circulating liquid, and the circulation of the treated liquid is based on the measurement result of the flow velocity of the permeated liquid obtained by the correction. The cross-flow filtration method according to Appendix 11, which determines the termination of the above.

(Supplementary Note 13) The cross-flow filtration method according to any one of Supplementary note 7 to 12, wherein the treatment liquid is a nanocarbon dispersion liquid in which nanocarbon and a nonionic surfactant are dispersed in a solvent.

(Appendix 14) The cross-flow filtration method according to Appendix 13, wherein the nanocarbon is a single-walled carbon nanotube.

10,300 ... Cross-flow filtration device,
20 ... Filter module,
21 ... Inner tank,
22 ... Outer tank,
23 ... Semipermeable membrane,
24 ... Discharge port,
30 ... Treatment liquid tank,
31 ... Suction tube,
32 ... Recovery tube,
33 ... Injection tube,
40 ... Pump,
50 ... Pressure regulator,
60 ... Replenishment liquid tank,
61 ... Suction tube,
62 ... Ventilation pipe,
70 ... Control unit,
80 ... Replenisher measuring unit,
90 ... First pressure sensor,
100 ... Second pressure sensor,
110 ... Third pressure sensor,
120 ... Permeate tank,
121 ... Recovery tube,
122 ... Ventilation pipe,
130 ... Permeate measuring unit,
141 ... First tube,
142 ... Second tube,
143 ... Third tube,
144 ... 4th tube,
151,152,153,154,155,156,157 ... Cable,
200 ... Treatment liquid,
210 ... Replenisher,
220 ... Permeate,
310 ... First flowmeter,
320 ... Second flow meter.

Claims (11)

A filter module with an inner and outer tanks separated by a semipermeable membrane,
An airtight treatment liquid tank that houses the treatment liquid,
A pump that circulates the treatment liquid to the inner tank and the treatment liquid tank of the filter module, and
A replenishment liquid tank for accommodating the replenishment liquid to be replenished in the treatment liquid tank, and
With at least one or more sensors measuring the pressure of the circulating treatment liquid,
A replenisher liquid measuring unit for measuring the amount of the replenisher liquid supplied from the replenisher liquid tank to the treatment liquid tank is provided.
A cross-flow filtration device characterized in that the replenisher liquid is continuously replenished in the treatment liquid tank. A filter module with an inner and outer tanks separated by a semipermeable membrane,
A treatment liquid tank that houses the treatment liquid and
A pump that circulates the treatment liquid to the inner tank and the treatment liquid tank of the filter module, and
A replenishment liquid tank for accommodating the replenishment liquid to be replenished in the treatment liquid tank, and
With at least one or more sensors measuring the pressure of the circulating treatment liquid,
A replenisher liquid measuring unit for measuring the amount of the replenisher liquid supplied from the replenisher liquid tank to the treatment liquid tank is provided.
The replenisher liquid is continuously replenished to the treatment liquid tank, and the replenisher liquid is continuously replenished.
On the basis of the amount of replenisher, the treatment liquid torque Rosufuro filtering device comprises a control unit for controlling the amount of circulating into the tank from the processing liquid tank by the pump. The cross-flow filtration device according to claim 1 or 2, wherein the replenishment liquid measuring unit measures the flow velocity of the replenishment liquid supplied from the replenishment liquid tank to the treatment liquid tank. A filter module with an inner and outer tanks separated by a semipermeable membrane,
A treatment liquid tank that houses the treatment liquid and
A pump that circulates the treatment liquid to the inner tank and the treatment liquid tank of the filter module, and
A replenishment liquid tank for accommodating the replenishment liquid to be replenished in the treatment liquid tank, and
With at least one or more sensors measuring the pressure of the circulating treatment liquid,
A replenisher liquid measuring unit for measuring the amount of the replenisher liquid supplied from the replenisher liquid tank to the treatment liquid tank is provided.
The replenisher liquid is continuously replenished to the treatment liquid tank, and the replenisher liquid is continuously replenished.
The replenishment liquid measuring unit is a cross-flow filtration device that measures the flow velocity of the replenishment liquid supplied from the replenishment liquid tank to the treatment liquid tank. The cross flow according to claim 3 or 4 , further comprising a control unit that controls the circulation amount of the treatment liquid from the treatment liquid tank to the inner tank by the pump based on the flow rate of the replenishment liquid. Filtration device. The cross-flow filtration device according to claim 1 or 2, wherein a permeate measuring unit is provided at the outlet of the outer tank to measure the flow velocity of the permeate. The cross-flow filtration device according to claim 6 , further comprising a control unit that controls the circulation amount of the treatment liquid from the treatment liquid tank to the inner tank by the pump based on the flow rate of the permeated liquid. .. A cross-flow filtration method using the cross-flow filtration device according to any one of claims 1 to 7.
A step of circulating the treatment liquid to the inner tank and the treatment liquid tank, and
A cross-flow filtration method comprising a step of determining the end of circulation of the treatment liquid according to the amount of the replenishment liquid in the replenishment liquid tank. Based on the pressure of the treatment liquid on the inlet side of the inner tank, the pressure of the treatment liquid on the outlet side of the inner tank, and the pressure of the permeate liquid that has permeated the semipermeable membrane on the discharge port side of the outer tank. The cross-flow filtration method according to claim 8 , further comprising a step of adjusting the circulation amount of the treatment liquid to the inner tank. The cross-flow filtration method according to claim 8 or 9 , wherein the treatment liquid is a nanocarbon dispersion liquid in which nanocarbon and a nonionic surfactant are dispersed in a solvent. The cross-flow filtration method according to claim 10 , wherein the nanocarbon is a single-walled carbon nanotube.

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